Note 53 — COLOURS and COLOURING.

The French translation of 1716 has a note on this chapter, saying, that the invention of enamel painting found out since the time of Leonardo da Vinci, would better answer to the title of this chapter, and also be a better method of painting. I must beg leave, however, to dissent from this opinion, as the two kinds of painting are so different, that they cannot be compared. Leonardo treats of oil painting, but the other is vitrification. Leonardo is known to have spent a great deal of time in experiments, of which this is a specimen, and it may appear ridiculous to the practitioners of more modern date, as he does not enter more fully into a minute description of the materials, or the mode of employing them. The principle laid down in the text appears to me to be simply this: to make the oil entirely evaporate from the colours by the action of fire, and afterwards to prevent the action of the air by the means of a glass, which in itself is an excellent principle, but not applicable, any more than enamel painting to large works.